mastoGem/server.go

package main

import (
	"crypto/tls"
	"log"
	"net"
	"net/http"
	"os"
	"fmt"
	"encoding/json"
	"io/ioutil"
	"strings"
	"html"
	"regexp"
)

type Blog struct {
	Id      string `json:"id"`
	Content string `json:"content"`
	Date    string `json:"created_at"`
}

type Config struct {
	Listen   string `json:"listen"`
	CertPath string `json:"cert_path"`
	KeyPath  string `json:"key_path"`
	BaseURL  string `json:"base_url"`
}

func main() {
	config := getConfig()

	listener := listen(config.Listen, config.CertPath, config.KeyPath)
	log.Println("Server successfully started")
	log.Println("Server is listening at " + config.Listen)

	serve(listener, config.BaseURL)
}

func getConfig() Config {
	configPath := os.Getenv("MASTOGEM_CONFIG_PATH")
	if configPath == "" {
		log.Println("MASTOGEM_CONFIG_PATH was not set, using default settings")

		config := Config{
			Listen: "127.0.0.1:1965",
			CertPath: "cert.pem",
			KeyPath: "key.rsa",
			BaseURL: "https://mamot.fr",
		}

		return config
	}

	configFile, err := ioutil.ReadFile(configPath)
	if err != nil {
		log.Fatalln("config file: %s", err)
	}

	var config Config

	json.Unmarshal(configFile, &config)

	return config
}

func listen(address, certFile, keyFile string) net.Listener {
	cert, err := tls.LoadX509KeyPair(certFile, keyFile)
	if err != nil {
		log.Fatalln("loadkeys: %s", err)
	}
	config := &tls.Config{
		ClientAuth:   tls.RequestClientCert,
		Certificates: []tls.Certificate{cert},
		MinVersion:   tls.VersionTLS12,
		InsecureSkipVerify: true,
	}

	listener, err := tls.Listen("tcp", address, config)
	if err != nil {
		log.Fatalln("failed to listen on 0.0.0.0:1965: %s", err)
	}

	return listener
}

func serve(listener net.Listener, baseURL string) {
	for {
		conn, err := listener.Accept()
		if err != nil {
			log.Println(err)
		}

		go handleConn(conn.(*tls.Conn), baseURL)
	}
}

func handleConn(conn *tls.Conn, baseURL string) {
	defer conn.Close()

	blogs := getBlog(baseURL, "138624")

	_, err := fmt.Fprintf(conn, "20 text/gemini\r\n# Picasoft account toots\n")
	if err != nil {
		log.Println("handleConn: %s", err)
		return
	}

	for _, blog := range blogs {
		date := "```\n* Posted at " + blog.Date + "\n```\n"

		text := blog.Content + "\n"
		text = strings.ReplaceAll(text, "<p>", "")
		text = strings.ReplaceAll(text, "</p>", "\n\n")
		text = strings.ReplaceAll(text, "<br />", "\n")
		text = strings.ReplaceAll(text, "</a>", "")
		text = strings.ReplaceAll(text, "</span>", "")
		regexString := "<a( [^>]*)?>"
		regex, err := regexp.Compile(regexString)
		if err != nil {
			log.Println("regex: %s", err)
			return
		}
		text = regex.ReplaceAllLiteralString(text, "")
		regexString = "<span( [^>]*)?>"
		regex, err = regexp.Compile(regexString)
		if err != nil {
			log.Println("regex: %s", err)
			return
		}
		text = regex.ReplaceAllLiteralString(text, "")
		text = html.UnescapeString(text)

		_, err = fmt.Fprintf(conn, date + text)
		if err != nil {
			log.Println("read blogs: %s", err)
			return
		}
	}
}

func getBlog(baseURL, account string) []Blog {
	if baseURL == "" || account == "" {
		log.Println("baseURL or account is empty")
		return nil
	}

	resp, err := http.Get(baseURL + "/api/v1/accounts/" + account + "/statuses?exclude_reblogs=true")
	if err != nil {
		log.Println("Mastodon API request: %s", err)
		return nil
	}

	defer resp.Body.Close()

	if resp.StatusCode != 200 {
		log.Println("Mastodon API response: %s", resp.Status)
		return nil
	}

	body, err := ioutil.ReadAll(resp.Body)
	if err != nil {
		log.Println("Mastodon response body: %s", err)
	}

	var blogs []Blog
	json.Unmarshal(body, &blogs)

	return blogs
}